The Thermal Cycloaddition of Dispirodeca-4,9-diene to Isolated Carbon-Carbon Multiple Bonds

Article abstract of DOI:10.1246/bcsj.53.709

The cycloadditions of dispiro<2.2.2.2>deca-4,9-diene (1) to isolated carbon-carbon multiple bonds have proceeded in two different modes, giving dispiro<2.2.4.2>dodeca-4,11-diene and tricyclo(6.4.0.0^3,6>dodeca-2,7-diene derivatives.Mono- and 1,2-disubstituted olefins and acetylenes gave the former adducts, whereas 1,1-disubstituted olefins gave the latter, as the major products.Evidence for the intermediacy of biradicals is provided.The observed difference in the mode of the cycloaddition is explained in terms of the stereoelectronic and/or steric effect in the transition state for the cyclization of the intermediate.The addition of 1 to tetracyanoethylene (TCNE) in wet acetone has proceeded via a zwitterionic intermediate(s), giving a 1:1:1 adduct of 1, TCNE, and water.